In the course of its distribution, an item often finds itself moving along a production line. As it does so, it encounters item-interaction units. Examples of such item-interaction units include printers or RFID stations for encoding information on the item, or scales that weigh the item, or various mechanical actuators to move the item in particular ways.
A production line typically includes a conveyor belt that transports items past these item-interaction units. As the item approaches an item interaction unit, a sensor detects its arrival. The sensor signals the item-interaction unit, which then waits for a suitable interval to allow the item to reach an optimal interaction position. Once the item reaches that position, the item-interaction unit executes an interaction.
In many cases, a successful interaction with an item requires that the relative locations of the item-interaction unit and the item at the moment of interaction be correct. For example, if the item-interaction unit is a printer, and if a mark is to be printed on the top of a box, the print head should be at the top of the box at the moment of interaction. If the item-interaction unit is a weighing scale, the item should be centered on the scale's platform at the moment of interaction.
Since items can have many different sizes and shapes, the location of an item-interaction unit may have to change from time to time. For example, for tall items, a print-head may have to be moved up; whereas for short items, the print-head may have to be moved down. Without some means for reconfiguration, a production line will therefore accommodate only limited types of items.
In known production lines, such item-specific reconfiguration is a difficult procedure carried out manually at infrequent intervals. Because of the difficulty associated with reconfiguration, such production lines are typically dedicated to one type of item. As a result, production lines lack the flexibility to accommodate many different types of items on an as-needed basis.